Rhodamine based fluorescence turn-on chemosensor for nanomolar detection of Fe³⁺ ions

A new fluorescent chemosensor 3 based on rhodamine was synthesized which exhibit selective fluorescence enhancement behaviour in the presence of Fe³⁺ ions. The spirolactam ring-opening reaction is selectively induced by the Fe³⁺ ions among the various metal ions tested with a detection limit up to nanomolar range. Thus, receptor 3 behaves as an efficient ‘Turn On’ fluorescence as well as colorimetric chemosensor for the Fe³⁺ ions